The invention relates to a steering assembly for motor cars having a fixed casing tube which centrally houses a steering column in its interior. The steering column is enclosed at an upper region in front of a steering wheel by two covering segments arranged side by side. A steering wheel hub is located adjacent said upper region and is connected to spokes of the steering wheel which pass through an opening between the two covering segments. At least one of the two covering segments, which is remote from the steering wheel, being rotatively locked relative to the casing tube.
A steering assembly of this general type is known from German patent application DE-OS 3,437,214. There, the covering segment more remote from the drive is locked by fastening webs to a housing which is fastened to a casing tube. The covering segment located closer to the driver and arranged above the remote segment is coupled to the latter by a pinion shaft.
The spokes and the hub of the steering wheel execute a movement relative to these fixed covering segments. However, due to the rotation gap between the covering segments which is necessary for this relative movement, there is a greater danger of the steering wheel suddenly becoming obstructed in its rotation by a part, which may be a portion of a glove, a shawl or of a flexible key case, happening to enter this rotation gap, with the result that the vehicle can no longer be steered.
In order to reduce this danger, masking parts which are fastened to the steering wheel hub and move with the latter, are provided in the above-mentioned specification.
However, such masking parts are necessarily fixedly arranged and are only effective if they cover the rotation gap with a very small interval and which can only be used for covering segments which are absolutely circular and in the shape of the outer skin.
It is therefore an underlying object of the invention to provide for a mechanism for use in a generic steering assembly which would make such an obstruction to the rotation of the steering wheel, which is dictated by the covering segments, immediately ineffective to stop steering wheel rotation.
The object is achieved by having each covering segment which is rotatively locked to the casing tube with a connecting means which lockingly engages and disengages said covering segment. The locked segment is lockingly disengageable by an obstruction to rotation of at least one of the steering wheel hub or a spoke which would interfere with rotation of the steering wheel if the locking engagement were not disengaged. In this manner at least one of the two covering segments can rotate with the steering wheel. The connecting means can be reengaged after the obstruction of rotation ceases.
Due to the disengagement of the elements of the connecting means, which rotationally lock the covering segments, when a torque exceeding a threshold value is introduced into the respective covering segment by the occurrence of an obstruction preventing rotation of the steering wheel hub or of a spoke, the covering segments can rotate together with the steering wheel and therefore no longer obstruct the steering movement. After the part causing the obstruction have been removed, each released covering segment is rotated back into its initial position, where it is reengaged by its connecting element.
This solution of the problem is independent of the shape of the outer skin of the covering segment and is therefore universally useful.
As a simple construction of a connecting means used for the engaging disengaging rotational lock, spring-loaded catch balls can be used which are pressed out of their cup-shaped depression in a casing tube prolongation by the threshold torque action, and reengaged into it by a spring after the covering segment is rotated back. The threshold torque at which the catch ball disengages is then determined by the spring characteristic.
The invention is equally applicable to fixed covering segments near the driver for steering assemblies in which the covering segment near the driver rotates with the steering wheel. Here, only the covering segment remote from the driver need be disengageable from its rotationally stable position relative to the casing tube.
A further advantage is obtained when the covering segment, nearest the steering wheel, is adjoined by an impact absorber piece which is fastened on the fixed casing tube prolongation and is rotatable relative to the nearest covering segment.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.